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And some UNLISTEN doco too!

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Tom Lane 1998-10-08 00:19:13 +00:00
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<REFENTRY ID="SQL-UNLISTEN">
<REFMETA>
<REFENTRYTITLE>
UNLISTEN
</REFENTRYTITLE>
<REFMISCINFO>SQL - Language Statements</REFMISCINFO>
</REFMETA>
<REFNAMEDIV>
<REFNAME>
UNLISTEN
</REFNAME>
<REFPURPOSE>
Stop listening for notification on a notify condition
</REFPURPOSE>
<REFSYNOPSISDIV>
<REFSYNOPSISDIVINFO>
<DATE>1998-10-07</DATE>
</REFSYNOPSISDIVINFO>
<SYNOPSIS>
UNLISTEN <REPLACEABLE CLASS="PARAMETER">notifyname</REPLACEABLE> | "*"
</SYNOPSIS>
<REFSECT2 ID="R2-SQL-UNLISTEN-1">
<REFSECT2INFO>
<DATE>1998-10-07</DATE>
</REFSECT2INFO>
<TITLE>
Inputs
</TITLE>
<PARA>
</PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<REPLACEABLE CLASS="PARAMETER">notifyname</REPLACEABLE>
</TERM>
<LISTITEM>
<PARA>
Name of notify condition to stop listening to.
If "*", all current listen registrations for this backend are cleared.
</VARIABLELIST>
</REFSECT2>
<REFSECT2 ID="R2-SQL-UNLISTEN-2">
<REFSECT2INFO>
<DATE>1998-10-07</DATE>
</REFSECT2INFO>
<TITLE>
Outputs
</TITLE>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<replaceable>status</replaceable>
</TERM>
<LISTITEM>
<PARA>
<VARIABLELIST>
<VARLISTENTRY>
<TERM>
<returnvalue>UNLISTEN</returnvalue>
</TERM>
<LISTITEM>
<PARA>
Acknowledgement that statement has executed.
</PARA>
</LISTITEM>
</VARLISTENTRY>
</variablelist>
</LISTITEM>
</VARLISTENTRY>
</VARIABLELIST>
</REFSECT2>
</REFSYNOPSISDIV>
<REFSECT1 ID="R1-SQL-UNLISTEN-1">
<REFSECT1INFO>
<DATE>1998-10-07</DATE>
</REFSECT1INFO>
<TITLE>
Description
</TITLE>
<PARA>
UNLISTEN cancels any existing registration of the current
<productname>Postgres</productname> backend as a listener on the notify
condition <REPLACEABLE CLASS="PARAMETER">notifyname</REPLACEABLE>.
The special condition name "*" means to cancel all listener registrations
for the current backend.
<para>
The backend does not complain if you UNLISTEN something you were not
listening for.
<para>
Each backend will automatically execute <command>UNLISTEN "*"</command> when
exiting.
<para>
The reference page for <command>NOTIFY</command> contains a more extensive
discussion of the use of <command>LISTEN</command> and
<command>NOTIFY</command>.
<REFSECT1 ID="R1-SQL-UNLISTEN-2">
<TITLE>
Usage
</TITLE>
<PARA>
<ProgramListing>
postgres=> listen virtual;
LISTEN
postgres=> notify virtual;
NOTIFY
ASYNC NOTIFY of 'virtual' from backend pid '12317' received
postgres=> unlisten virtual;
UNLISTEN
postgres=> notify virtual;
NOTIFY
-- notice no NOTIFY event is received
postgres=>
</ProgramListing>
</REFSECT1>
<REFSECT1 ID="R1-SQL-UNLISTEN-3">
<TITLE>
Compatibility
</TITLE>
<PARA>
<REFSECT2 ID="R2-SQL-UNLISTEN-4">
<REFSECT2INFO>
<DATE>1998-10-07</DATE>
</REFSECT2INFO>
<TITLE>
SQL92
</TITLE>
<PARA>
There is no <command>UNLISTEN</command> in <acronym>SQL92</acronym>.
</REFENTRY>